Method and apparatus for cleaning articles



y 9, 1933- K. J.- R. ROBERTSON 1,907,875

METHOD AND APPARATUS FOR CLEANING ARTICLES Filed June 17 1929 PatentedMa 9, 1933 UNITED STATES PATENT OFFICE KENNEI'H JAMES .RENNIE ROBERTSON,OI LONDON, ENGLAND, ASSIGNOR TO CARRIER ENGINEERING COMPANY LIMITED, 01LONDON, ENGLAND METHOD AND APPARATUS FOR CLEANING ARTICLES Applicationfiled June 17, 1929, Serial No. 371,554, and in Great Britain May 10,1929.

This invention relates to a method and apparatus for cleaning greasyarticles, and has particular reference to cleaning castings, forexample, motor car parts.

The main object of the invention is to provide a method and apparatusfor cleaning articles by which any soluble matter is removed by asolvent action, and any residue or extraneous matter subsequentlyremoved from the articles by physical or washing operation preferablyalso by a solvent.

Further and favourable objects of the invention will appear fromthefollowing description.

A method of cleaning greasy articles according to the present inventioninvolves subjecting the articles to the action of sprays of a solventfor the grease whereby the grease is removed by physical and solventaction.

Conveniently, grease charged solvent may be distilled and the vapourcondensed, the refined solvent so obtained being either wholly or inpart directed under pressure in the form of sprays on to the articles.

Preferably, the method of cleaning greasy articles according to theinvention consists in subjecting the articles to a vapour solvent forthe grease, the articles being at a temperature causing condensation ofthe vapouron the articles and subsequently to the action of sprays ofthe solvent whereby a solvent and physical cleaning action is attained.

Preferably, also, this method of treatment is characterized bydistilling the condensate, and condensing the vapour soobtained toprovide a refined liquid solvent, the whole or part of the condensatebeing used in the sprays by which the articles are treated, the sprayingbeing preferably effected just prior to the articles leaving thecleaning zone.

An apparatus for cleaninggreasy' articles according to the invention maycomprise a bath open to atmosphere, means for supplying vapour solventto the bath, and refrigcrating means for limiting the level of thevapour in combination with a spray device including means forwithdrawing condensed vapour from the bath, separating the oil therefromand returning the refined solvent in the form of sprays.

In the preferred form of apparatus, stills are included into which thecondensed vapour may flow, and a condensing vessel is provided which isdisposed to receive the distilled vapour from the stills, together withpressure means for delivering the condensate in the condensing vesselinto the cleaning bath in the form of sprays.

A cleaning bath, which is in communication with atmosphere, and providedwith means for forming a refrigerating or cooling zone to limit theheight of thevapour in the bath, may have the zone formed by providingcooling coils in the walls of the bath within or without, or both, orthe walls may be sprayed with a cooling liquid, and so as to provide anadditional means of preventing the exit of vapour where the bath is incommunication with the atmosphere, a canopy or hood may be provided,thereby forming a tortuous path for the exit of the vapour comprisingpockets of trapped atmospheric air which are retained, and theirtemperature controlled so as to absorb dissipating vapour and to returnthevapour to the collectors to the bath by reducing the temperature ofthe pockets to dew point.

Reference will now be had to the accompanying drawing where theinvention is shown embodied in a vapour cleaning plant and where:

Fig. 1 illustrates in section and diagrammatically a simplifiedembodiment of the invention associated with a solvent vapour bath forcleaning articles; and

Fig. 2 is a longitudinal section of a praotical form of the invention.

Referring now to the .drawing but first more particularly to Fig. 1, atrough-like bath or duct 1 is arranged with a canopy or hood 2 aboutwhich is disposed a conveyor 3 carried by rollers 4, the conveyor cycleis diagrammatic embodiment illustrated stills 6 communicating with inletnozzles 7 in the side of the duct 1 constituting the bath maintain theduct 1 supplied with solvent vapour so that articles 5 traversedtherethrough on the conveyor 3--usually at a temperature below thecondensation temperature of the vapour-have the grease and othervsoluble extraneous matter on their surfaces removed by the vapourcondensin on their surfaces and effecting solution of t e grease andsolu ble matter which in solution falls to the base 8 of the bath and isthere led off through a conduit 9, say to the stills 6for regenerationof the vapour which is again supplied to the bath.

Suitable heating means are associated with the regenerating stills 6 andthe vapour preferably of the nature described in my co-pendingapplication Serial No. 302,038, while the refrigerating zone produced byrefrigerant coils 10, 11, may also be conveniently provided to preventleakage of the vapour by diffusion at the entry 12 and the exit 13 tothe duct 1 constituting the bath.

In accordance with the invention the articles 5 to be cleaned aresubjected to a spray action preferably by a solvent, and to this end aspray nozzle 14 is shown juxtaposed to the exit 13 of the bath so thatthe articles 5 in their continued traverse on the conveyor 3 are, aftersolvent treatment by the vapour of the bath, subjected to the physicalspray action of-the nozzle 14 which preferably ejects liquid spray ofthe solvent employed in the vapour treatment, say trichlorethylene.

The supply of spray liquid for the nozzle 14 in the embodiment referredto, is obtained from the stills 6, regenerated and refined vapoursolvent from which feeds to a condensing tank 15 through a conduit 16and the tank is maintained cool by refrigerating coils 17 through whichrefrigerant is circu-' lated, cold water being adequate to condense thesolvents customarily employed, but if required brine or other suitablerefrigerant can be utilized.

Solvent is also supplied to the condensing tank 15 through a conduit 18communicating direct with r the duct 1 and condensed solvent from thetank 15 fed to the spray noz- -zle 14 by a centrifugal pump 19 through asupply conduit 20, the nozzle 14 being arranged so that a shower of thesolvent liquor is projected upon the surfaces of the articles 5 duringtheir traverse through the duct 1 in the vicinity of the nozzle.

Conveniently, a separate still 6 is employed to feed the condensing tank15 of the solvent. liquor for, the spray nozzle 14, such still supplyingrefined vapour to the condensing tank 15 for condensation, as it will beunderstood that should solvent containing any appreciable proportion ofgrease be employed for the spra the ph sical detergent action is consierably r need, and in some cases grease deposited on the surfaces of thearticles instead of residue matter being removed as is the case whenrefined solventliquor is projected from the nozzle 14.

- Residue rease and dirt from the stills 6 can be co lected, say, atintervals through discharge cocks 21, and if of value as a lubricant maybeflstored in barrels, while, further, in place of the single spraynozzle 14 a plurahty of nozzles -can be employed in order that a showerof spray li uor may be projected on all the surfaces 0 the armcles 5traversing the duct 1 in spite of irstituted by the duct 25 and thespray bath constituted by the duct 27 respectively and being extendedinwardly at 30 so as to form a. continuous cover over the vapour andspray baths leaving them open to atmosphere only at the entry 31 andexit 32 respectively Provi ed on the canopies 28 and 29 is a conveyor 33carried by guide rollers 34, and arranged to traverse articles such as35 to be cleaned in sequence from the entry 31, throu h the vapour bath25 and the spray bat 27, to the exit 32 for delivery.

Loss of vapour from the bath 25 by diffusion through the entr 31 isprevented by the provision of cooling coils 36 carrying refrigerantadjacent the mouth of the bath 25, which efi'ect condensation of vapourattaining their vicinity as in my co-pending application Serial No.302038, and the articles 35 traversing the vapour zone of the bath 25are at a temperature below the condensation temperature of theparticular .va-

pour employed, so as to effect its condensapose of removing residueextraneous matter from their surfaces.

The spray bath 27 is maintained at a temperature sufficiently low toensure that all vapour in the bath is condensed by means of coils 38, 39and 40 lining the Walls and base of the bath and carrying a suitablerefrigerant, the temperature required being dependent on the particularsolvent employed, but with the customary solvent such astrichlorethylene a temperature produced by the circulation of cold waterin the pipes 38, 39 and 40 being sufficient.

A duct 41 is arranged in the base 42 of the spray bath 27 to collectsolvent liquor and convey it through a pipe 43 to a still 44 wherein thesolvent isrecirculated, pure vapourized solvent passing through aconduct 45 including a suitable stop valve 46 to a condensing tank 47and residue grease and dirt being collected in the base of the still 44and discharged as required through a drain cock 48.

The necessary heat to produce vapourization of the solvent in the still44 may be provided by heating pipes or in any other suitable manner, aburner 49 being employed in the embodiment illustrated.

The condensation of the refined vapour supplied to the tank 47 iseffected by means of cooling coils 50 through which cold water or otherrefrigerant is circulated so that a head of solvent liquor is maintainedin the base of the tank 47 being drawn off by a pump 51 and suppliedunder pressure through a conduit 52 to a pair of spray nozzles 53 and 54so'llocated in the spray bath 27 that the articles 35 passingtherethrough on the conveyor 33 are subjected to a rigorous detergentaction by the impingement on their surfaces of the solvent liquorejected under pressure from the nozzles 53 and 54. s

The supply of refined vapour from the still 44 to the condensing tank 47may be regulated at the instance of the level of condensed liquor in thetank, and any surplus vapour may be conveyed to the va our bath 25, saythrough the conduit 55 which may normally be maintained closed.

In operation the articles 35 are fed to the conveyor 33 at 31, and inpassing through the vapour bath 25 have the grease and other solublematter removed from their surfaces the solvent liquor emitted by thenozzles 53' and 54 effects removal of any dirt and foreign matter, aswell as residue grease, the

low temperature at which the bath 27 is' maintained preventing anyconsiderable loss of solvent by diffusion through the exit 32 required,and vapour losses being further the canopies 28 and 29.

Although in the examples illustrated the apparatus is constructed so asto employ the same. solvent for both the vapour cleaning and spraycleaning operations, it will be seen that the embodiment illustrated inFig. 2 is readily adapted for the use of different sol- Vents whererequired, but owing to the desirability and importance of maintainingthe solvent liquor employed in the spray cleaning operation, free fromdissolved matter, a readily volatile liquid is more convenientlyemployed, and as such the vapour solvents such as trichlorethylene bestsuited for the vapour cleaning operations, are equally employed withadvantage in the spray cleaning operation according to the invention.

The combined physical and solvent action provided according to theinvention ensures adequate cleansing of the articles treated byeffecting simultaneous removal of both soluble and insoluble matter as acontinuous operation.

What I claim is 1. A method of cleaning articles having greasy surfacesconsisting in immersing the articles within a solvent vapor bath andthen spraying the articles with a solvent in liquid form. a

2. A method of removing grease and oleaginous substances from thesurface of an object consisting in immersing the object within a solventin vaporous form, to cause condensation of the vapor on the object andthen removing residue from the surface by flowing solvent in liquid formthereover.

3. A method of cleaning objects having irregular surfaces consisting inabsorbing grease upon said surfaces by immersing said surfaces within asolvent vapor at a higher temperature than the surfaces so that thevapor will condense, in part, upon the surfaces, and then subjecting thesurfaces to a flood of hot liquid solvent.

4. A system of the character described comprising a first bath, a secondbath, both baths being open to the atmosphere, means for traversingarticles to be cleaned successively through said first bath and secondbath, means for supplying a solvent in vaporous form to said first bath,cooling means for controlling the level of said vapor in the first bathand second bathand spraying means for discharging a solvent in liquid'formnpon articles passing through the second bath after emerging fromthe first bath.

"Signed at London, England, this 4th day of -June, 1929. I

KENNETH JAMES RENNIE ROBERTSON.

where the articles are discharged clean as

